This invention relates to a technique for three-dimensionally scanning with an ultrasonic beam in an object to be examined, particularly to a two-dimensional array ultrasonic probe being capable of three-dimensional scanning with an ultrasonic beam in the object by an electronic control and an ultrasonic diagnostic apparatus comprising it.
Recently an ultrasonic diagnostic apparatus that transmits and receives an ultrasonic beam with an ultrasonic probe and three-dimensionally scans in the object, and corrects a three-dimensional data from the object, and makes a three-dimensional image to supply for diagnosis is developing. In the first example of such apparatus, a three-dimensional image data is corrected by moving in parallel and mechanically on the surface of an object an ultrasonic probe arranged a plurality of transducer elements in one direction. And there is an apparatus that scanning of beam is performed with inclining consecutively contact angle of said probe to the object from one side to another without changing contact position between the probe and the object.
In addition, in the second example, 2D-array ultrasonic probe is composed with 64xc3x9764 elements arrayed in two-dimensional direction. An ultrasonic beam with gimlet shape is transmitted and received in or from interior of the object by using a specified transducers fixedly selected in said 2D arrangements, and a three-dimensional image data is corrected from the object to be examined. In addition, a two-dimensional probe is a probe that an arrangement of elements is expanded from one direction to two directions. For example it is disclosed in Ultrasonic Imaging 14, 213-233 (1992); IEEE Trans. UFFC 38, 100-108 (1991).
However, in these traditional ultrasonic diagnostic apparatus, in said first example, an ultrasonic probe and an ultrasonic diagnostic apparatus had to be large and heavy because a driving system for scanning an ultrasonic beam and moving a probe mechanically is necessary. Therefore, small and light two-dimensional probe is desired from an operator on operational view. In addition, a scanning range is basically restricted by said composition of driving system, so an arbitrary range can not be scanned. Furthermore, said mechanical scanning mechanism causes abrasion. So its life times are short.
In the second example, only the fixedly selected specified elements in two-dimensional array transducer elements are used for transmitting and receiving to scan electrically an ultrasonic beam with gimlet shape. So a region for correcting three-dimensional data was narrow. In addition, even element number used in transmitting and receiving is specified as a part of 64xc3x9764, but is necessary about 256. So number of cables connected to each element needs a lot. And if number of transducer element for transmitting and receiving ultrasound is increasing, number of beam forming circuit disposed on main body of diagnostic apparatus needs also a lot.
Thus in view of previously described subject, the first object of the present invention is to provide small and light ultrasonic probe that is able to three-dimensional scan with transmitting and receiving an ultrasonic beam to the object to be examined.
The second object of the present invention is to provide a two-dimensional array probe that is easy to contact to the surface of the object to be examined.
The third object of the present invention is to provide an ultrasonic probe that is able to three-dimensional scan to the object to be examined with an ultrasonic beam without using mechanical scanning mechanism such as previously described.
The fourth object of the present invention is to provide an ultrasonic probe that a three-dimensional image data can be acquired from wide range of the object to be examined.
The fifth object of the present invention is to reduce number of cable for connecting an ultrasonic probe and a main body of diagnostic apparatus, and to provide an ultrasonic diagnostic apparatus that an operator is not influenced by weight and hardness of cable when the operator operates said probe.
Furthermore, the sixth object of the present invention is to provide an ultrasonic diagnostic apparatus being capable of transmitting and receiving with a two-dimensional array probe and having a few beam forming circuits.
And the seventh object of the present invention is to provide an ultrasonic diagnostic apparatus being obtained good quality image and being capable of dynamic focusing with two-dimensional array probe.
In order to achieve said object, an ultrasonic probe in the first invention comprises plural number of transducer element for transmitting and receiving ultrasound arrayed in two-dimensional direction and correcting an ultrasonic signal. And said plural number of transducer element are arrayed with convex shape to transmitting direction in at least one direction or two directions, which two directions are perpendicular to each other. And in an ultrasonic probe having convex shape in two directions, the transducer arrangement in this two direction is preferable to apply radial arrangement in two directions, or one radial arrangement and one parallel arrangement.
In addition, an ultrasonic probe of the present invention has an element selecting switch circuit for selectively switching arbitrarily transducer elements for transmitting and receiving ultrasound in the neighborhood of said two-dimensional array transducer elements. An output line of said element selecting switch circuit is connected to each element of arrayed transducer and number of input lines is less than that of arrayed transducer.
In the probe of the present invention, an arbitrary transducer can be selected by controlling signal to said element selecting switch circuit. Accordingly diameter with arbitrary shape can be formed. In addition, this diameter can be moved by the controlling signal to element selecting switch circuit. Three-dimensional scanning to interior of the object is possible by this motion of diameter with ultrasonic beam.
In order to achieve said object, in the present invention a related invention to said ultrasonic probe as a specified invention is disclosed. An ultrasonic diagnostic apparatus in the related invention of the preset invention comprises an ultrasonic probe including a two-dimensional array probe having minute ultrasonic transducer elements, element selecting means for supplying data to select elements transmitting and receiving ultrasound from array transducer of said ultrasonic probe, means for supplying bundling data for bundling and connecting said selected transducer elements to plural number of group, means for transmitting ultrasound to the object with applying the predetermined transmitting delay time to said bundled transducer element groups, means for beam forming with receiving signals of said each bundled transducer group, means for image processing output signal of this beam forming means, and an image display means.
In this related invention, it is a characteristic that the transducers bundled to said plural number of group form fresnel ring having a concentric circle. And the ring is designed such that the difference between a maximum and a minimum distance, which is distance between transducer element in each ring forming said fresnel ring and ultrasonic focus point, is less than xe2x85x9 wave length of ultrasound.
In said ultrasonic diagnostic apparatus, the form of said fresnel ring is not changed during an echo signal is received. And means for controlling said beam forming circuit corresponding to a received signal of each ring so as to move receiving focus point continuously on the center axis line of fresnel ring is comprised. Furthermore, said apparatus comprises means for changing form of said fresnel ring corresponding to the depth of receiving focus point, means for ultrasonic scanning the predetermined depth region in the object with each form of said fresnel ring, and means for composing an image from echo signal acquired at each depth region, necessarily.
Moreover an ultrasonic diagnostic apparatus of the related invention preferably comprises a two-dimensional array probe for transmitting and receiving ultrasound to the object, a main body of diagnostic apparatus for acquiring and displaying an ultrasonic image of diagnostic part in the interior of the object by using an ultrasonic signal corrected with this two-dimensional array probe, and data transmitting part for inputting and outputting a selecting data of transducer elements and said corrected ultrasonic signal from one direction to another between said two-dimensional array ultrasonic probe and said main body.